One More
The net/net of the posting is that there are no easy formulas for determining an adequate DBA staffing level. It is a problem of complexity and the subjective nature of DBA talent levels. However, I did get an interesting response to that article from a DBA manager type. He said that his management always tells him that the number of database instances that he should be able to handle given his current staffing is always "one more."
Now that is sad. Funny, but sad. I guess the opposite of that statement could be true, too. In other words, when upper level management asks how many DBAs are needed the answer is always "one more."
Really, the truth is that solving the problem is not simple... and that creates confusion.... and simple answers like "one more" become the norm.